Process for the manufacture of copper alloys



Patented June 26, WZQ.

warren ares I DFFIQE;

raoonss non 'rnn man unaorunn or cornea annoys.

No Drawing. Applioatipn filed may 11, 1921, Serial 170.4%,580, and in Germany February 4, 1920.

(GRANTEDUNDER THE PROVISIQNS OF THE ACT OF MARCH 3, 1921, 41 STAT. In, 1818.)

In the manufacture of copper alloys with the aid of an intermediate alloy there is t h1s disadvantage that frequently the addition of the fluid intermediate alloy, owing to ts low volatilizing point can not exercise its full effects on the final alloy. The invention consists in this, that by making use of an auxiliary alloy, which is added after the admixing with the intermediate alloy, any defect arlsing in the latter operation is again compensated or removed.

An example for the practical carrying out of the invention is given in the process described below.

Use has already been made of the so-called cadmium alloys, and tin alloys are also known, but it-has become a demonstrated feature of such alloys that though the quantity of cadmium or tin added be comparativel great, a considerable proportion of this a dition is lost by volatilization, so that only an inadequate or at any rate a very variable residue of cadmium or tin remains in the alloy, the result of which is that the final alloy also exhibits a very variable percentage of cadmium or tin, and any products manufactured from the alloys, as, for instance, bronze-wires, turn out to be of very unequal quality. Owing to such imperfections the possibility of using these wires for such purposes for example as the conduction of electricity is very materially affected.

By taking advantage of the new process however, the operations may be so arranged that a considerably smaller quantity of cad-' mium or tin is made use of in the intermediate alloy but in spite of this a final alloy of a highly uniform and suficient cadmium or tin content is obtained, by the simple expedient of making use of an extra, or as it is called in this specification an auxiliary alloy, after the intermediate alloy has been added. Y

Example.

The first intermediate allow is compounded so asto contain not more than 1.5 parts of tin, 4.5 parts cadmium and 3 parts copper or not less than 0.6 parts tin, 2.2 parts cadmium and 1.5 parts copper.

The best proportion may perhaps be indicated to be 1 part tin, 3 parts cadmium, and 2 parts copper.

The process of smelting these together is now carried out in some such way as follows :-The previously weighed co per is put into a smelting crucible; when t e process is completed, the crucible is removed from the fire, the already weighed and warmed tin is then introduced into the crucible, so that a thinly fluid alloy results, at a temperature of from 600-100" C. To this alloy already heated quantities of cadmium are now also added, in the form of rods or bars, so that only the first of the latter melt rapidly and with copious evolution of smoke. If after addition of the entire quantity of cadmium, the allo should not have re mained fluid enoug then the crucible must be again placed over the fire and the contents vigorously stirred, and further heating continued till no evolution of brown vapours is longer noticeable.

The tin fluid alloy is now run, oil into small moulds and the cooled metal, which is now as brittle as glass, is easil broken to small piecesand then thorou h y mixed.

The first,- or intermediate a oy, is now ready. Subsequently it is utilized for the production of bronze-ingots or whatever the final product may be in the following manner.

100 kgs. of previously weighed electrolytic copper are melted down in a crucible and when the correct casting temperature has been reached, 200 gms. or .2 kgs. of phosphoric copper (or a corresponding quantity of amorphous phosphorus, about 2 tablespoonfuls packed in thin sheet copper), are inserted beneath the upper surface of the copper with tongs or the like, so that, without being burned, the phosphorus dissolves in the copper bath. The little phosphorus packet must not be larger than just to be exactly occupied and filled out by its contents and so that the latter cannot move inside the cover, after the projecting parts of the latter have been bent down and ham mered together.

The intermediate alloy is then added. This alloy which has been prepared in the form of fragments of copper sheet or tubes and has been heated, is put into a box, which, as in the case just described for phosphorus, must not be too large, and the box then rapidly inserted into the copper bath which is well agitated with a graphite stirrer. When this has been accomplished the so-called auxiliary alloy is next-added.

The latter consists of tin and aluminium or Jim of tin and magnesium (or cadmium) these two being present in equal proport1ons, so that, into the same crucible 25 kgs. aluminium and 25 kgs. tin or 25 kgs. tin and 25 kgs. magnesium (cadmium) are measured out.

The operation of smelting is conducted in such a manner that the aluminium 1s first fused; the tin is then added, which dissolves in the aluminium like sugar in water. It. is in this case immaterial whether the addition of magnesium is effected by initially melting the magnesium and adding tin simultaneously or subsequently. This auxiliary alloy is now put into a small box the same precautionary measures being observed as in the case of the intermediate alloy, and in oint of fact this auxiliary alloy is added bet fire the breaking up of the layer of coal dust or the like encrusting the upper surface when the crucible has been swung ofl' the fire. After the addition, the entire contents of the crucible are speedily and well stirred and the metal bath, as electrolytic copper, cast into vertical moulds.

By thus making use of the two alloys, of the intermediate one as well of the auxiliary one, it is possible to adjust the tensile strength and the electrolytic conductivity of the final product as desired and to control it completely, and it is even possible, by properly choosing the component ingredients of the intermediate alloy, which is formed of the readily combustible cadmium with tin and with co per and in spite oi the fact, that the quantity of cadmium added be a comparatively small one, to obtain a relatively high degree of etficiency due to the circumstance that this intermediate alloy also contains further copper. But the latter, as well as the tin surround the cadmium after their introduction to the smelting crucible so satisfactorily that only a very slight amount of volatilization can take place.

It will be noted from the exam les given that the first or intermediate al oy has a higher melting point than the second or auxiliary alloy, due to the large proportion of copper in the first alloy, and which has a higher melting point than any of the other metals mentioned. Thus the second or auxiliary alloy may be added after the first has been added and after the temperature of the copper with the first alloy has somewhat lowered.

Tin has the lowest meltin point of any of the metals mentioned and 1t will be noted from the examples given that it forms a larger percentage of the second-added alloy than it does of the first. As var ing amounts of the tin ma be volatilized rom the molten copper on er varying temperature and other conditions of operation, the desired amount of tin in the final alloy may be obtained by correspondingly varying the roraooe amount of the second or auxiliary alloy. From this standpoint the second or auxiliary alloy may be considered as a corrective alloy. Also I may obtain various different coppertin-cadmium alloys by merely varying the relative proportions of the two intermediate allo s The molten copper contains some copper oxide, and the intermediate alloy serves in part to remove this oxide by the burning up of some of one or more of the metals of the intermediate alloy. The intermediate alloy, particularly if it contains a large percentage of cadmium, will immediately eliminate the copper oxide dissolved in the copper bath as soon as said intermediate alloy is added, so that none of the metals of the auxiliary alloy will be consumed for this purpose. The metal losses thus occur chiefly in the intermediate alloy, and the extent of these losses will vary with the temperature of the bath, the amount of oxide present, and other conditions. By varying the relative proportions of the two alloys to be added, the known or estimated loss from the alloy first added, may be compensated for by a proper quantity of the second one added. Also, if certain metals, such as magnesium are to be incorporated in the final product, a serious difliculty is often encountered when the metal is added to the copper bath. Large metal losses occur, as well as the rendering of the mass very viscous. This difliculty is overcome by the use of my invention as the oxide is removed from the bath by the intermediate alloy and the magnesium or tllile like is included only in the auxiliary a 0y.

What I. claim is 1. A process of making copper alloys containing low fusing components and a high percentage of copper, by the use of intermediate alloys, which comprises adding the intermediate alloys in two parts to the molten copper, the first part added containing the lowest fusible component and the second part added containing higher fusible components.

2. A process of making alloys comprising a high percentage of copper and a low percentage of tin and cadmlum, by the use of intermediate alloys, which comprises adding the intermediate alloys in two parts to the molten copper, the first intermediate alloy added consisting of 1.5 to 3 parts by weight of copper, 0.6 to 1.05 parts by weight of tin and 2.2 to 4.5 parts by Weight of cadmium and the second containin tin in larger proportion in respect to its 0t er components.

3. A process of making copper alloys containing low fusing components, which consists 1n adding to the substantially pure litm copper an intermediate alloy containing approximately 1 part tin, 2 parts copper, and 3 parts cadmium, and adding a second intermediate alloy containing tin and cadmium in different proportions from those of the first mentioned intermediate alloy.

A process of making copper alloys containing low fusing components, which consists in adding to the molten copper an intermediate alloy containing tin and cadmium in approximately the proportion of 3 parts cadmium to 1 part tin, and adding a second intermediate alloy containing tin and cadmium in approximately equal parts.

5. A process of making copper alloys containing low fusing components, which con-- sists in adding to the molten copper two different intermediate alloys, both containing one or more of the same low fusing constituents but in different proportion in re spect to the other constituents, the amount added of one intermediate alloy in respect to the amount added of the other intermediate alloy being varied to vary the relative proportions of the low fusing constituents in the final product.

6. A process of making copper alloys containing low fusing components, which consists in adding to the molten copper two difierent intermediate alloys both containing one or more of the same lOW fusing constituents but in different proportion in respect to the other constituents, and varying the amount of the second intermediate alloy in accordance with the vaporization loss of the lowest fusing point constituent of the first intermediate alloy.

7. The process of making copper alloys having a high percentage of copper which consists in adding to a substantially pure molten copper an intermediate alloy acting to deoxidize the copper, and thereafter adding an auxiliary alloy including the metals to give the desired tensile strength.

8. The process of making copper alloys having a high percentage of copper which consists in adding to a substantially pure molten copper an intermediate alloy acting in part to deoxidize the copper, and thereafter adding an auxiliary alloy in an amount dependent upon the amount of the intermediate alloy consumed in said deoxidizing action.

Signed at WVien, Austria, this fifth day of March, 1921.

Inc. OSCAR v. ROSTHORN. 

